1 /*
2 * Copyright (C) 2010, 2011 Texas Instruments Incorporated
3 * Contributed by: Mark Salter (msalter@redhat.com)
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10 #include <linux/clockchips.h>
11 #include <linux/interrupt.h>
12 #include <linux/io.h>
13 #include <linux/of.h>
14 #include <linux/of_irq.h>
15 #include <linux/of_address.h>
16 #include <asm/soc.h>
17 #include <asm/dscr.h>
18 #include <asm/special_insns.h>
19 #include <asm/timer64.h>
20
21 struct timer_regs {
22 u32 reserved0;
23 u32 emumgt;
24 u32 reserved1;
25 u32 reserved2;
26 u32 cntlo;
27 u32 cnthi;
28 u32 prdlo;
29 u32 prdhi;
30 u32 tcr;
31 u32 tgcr;
32 u32 wdtcr;
33 };
34
35 static struct timer_regs __iomem *timer;
36
37 #define TCR_TSTATLO 0x001
38 #define TCR_INVOUTPLO 0x002
39 #define TCR_INVINPLO 0x004
40 #define TCR_CPLO 0x008
41 #define TCR_ENAMODELO_ONCE 0x040
42 #define TCR_ENAMODELO_CONT 0x080
43 #define TCR_ENAMODELO_MASK 0x0c0
44 #define TCR_PWIDLO_MASK 0x030
45 #define TCR_CLKSRCLO 0x100
46 #define TCR_TIENLO 0x200
47 #define TCR_TSTATHI (0x001 << 16)
48 #define TCR_INVOUTPHI (0x002 << 16)
49 #define TCR_CPHI (0x008 << 16)
50 #define TCR_PWIDHI_MASK (0x030 << 16)
51 #define TCR_ENAMODEHI_ONCE (0x040 << 16)
52 #define TCR_ENAMODEHI_CONT (0x080 << 16)
53 #define TCR_ENAMODEHI_MASK (0x0c0 << 16)
54
55 #define TGCR_TIMLORS 0x001
56 #define TGCR_TIMHIRS 0x002
57 #define TGCR_TIMMODE_UD32 0x004
58 #define TGCR_TIMMODE_WDT64 0x008
59 #define TGCR_TIMMODE_CD32 0x00c
60 #define TGCR_TIMMODE_MASK 0x00c
61 #define TGCR_PSCHI_MASK (0x00f << 8)
62 #define TGCR_TDDRHI_MASK (0x00f << 12)
63
64 /*
65 * Timer clocks are divided down from the CPU clock
66 * The divisor is in the EMUMGTCLKSPD register
67 */
68 #define TIMER_DIVISOR \
69 ((soc_readl(&timer->emumgt) & (0xf << 16)) >> 16)
70
71 #define TIMER64_RATE (c6x_core_freq / TIMER_DIVISOR)
72
73 #define TIMER64_MODE_DISABLED 0
74 #define TIMER64_MODE_ONE_SHOT TCR_ENAMODELO_ONCE
75 #define TIMER64_MODE_PERIODIC TCR_ENAMODELO_CONT
76
77 static int timer64_mode;
78 static int timer64_devstate_id = -1;
79
timer64_config(unsigned long period)80 static void timer64_config(unsigned long period)
81 {
82 u32 tcr = soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK;
83
84 soc_writel(tcr, &timer->tcr);
85 soc_writel(period - 1, &timer->prdlo);
86 soc_writel(0, &timer->cntlo);
87 tcr |= timer64_mode;
88 soc_writel(tcr, &timer->tcr);
89 }
90
timer64_enable(void)91 static void timer64_enable(void)
92 {
93 u32 val;
94
95 if (timer64_devstate_id >= 0)
96 dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_ENABLED);
97
98 /* disable timer, reset count */
99 soc_writel(soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK, &timer->tcr);
100 soc_writel(0, &timer->prdlo);
101
102 /* use internal clock and 1 cycle pulse width */
103 val = soc_readl(&timer->tcr);
104 soc_writel(val & ~(TCR_CLKSRCLO | TCR_PWIDLO_MASK), &timer->tcr);
105
106 /* dual 32-bit unchained mode */
107 val = soc_readl(&timer->tgcr) & ~TGCR_TIMMODE_MASK;
108 soc_writel(val, &timer->tgcr);
109 soc_writel(val | (TGCR_TIMLORS | TGCR_TIMMODE_UD32), &timer->tgcr);
110 }
111
timer64_disable(void)112 static void timer64_disable(void)
113 {
114 /* disable timer, reset count */
115 soc_writel(soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK, &timer->tcr);
116 soc_writel(0, &timer->prdlo);
117
118 if (timer64_devstate_id >= 0)
119 dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_DISABLED);
120 }
121
next_event(unsigned long delta,struct clock_event_device * evt)122 static int next_event(unsigned long delta,
123 struct clock_event_device *evt)
124 {
125 timer64_config(delta);
126 return 0;
127 }
128
set_periodic(struct clock_event_device * evt)129 static int set_periodic(struct clock_event_device *evt)
130 {
131 timer64_enable();
132 timer64_mode = TIMER64_MODE_PERIODIC;
133 timer64_config(TIMER64_RATE / HZ);
134 return 0;
135 }
136
set_oneshot(struct clock_event_device * evt)137 static int set_oneshot(struct clock_event_device *evt)
138 {
139 timer64_enable();
140 timer64_mode = TIMER64_MODE_ONE_SHOT;
141 return 0;
142 }
143
shutdown(struct clock_event_device * evt)144 static int shutdown(struct clock_event_device *evt)
145 {
146 timer64_mode = TIMER64_MODE_DISABLED;
147 timer64_disable();
148 return 0;
149 }
150
151 static struct clock_event_device t64_clockevent_device = {
152 .name = "TIMER64_EVT32_TIMER",
153 .features = CLOCK_EVT_FEAT_ONESHOT |
154 CLOCK_EVT_FEAT_PERIODIC,
155 .rating = 200,
156 .set_state_shutdown = shutdown,
157 .set_state_periodic = set_periodic,
158 .set_state_oneshot = set_oneshot,
159 .set_next_event = next_event,
160 };
161
timer_interrupt(int irq,void * dev_id)162 static irqreturn_t timer_interrupt(int irq, void *dev_id)
163 {
164 struct clock_event_device *cd = &t64_clockevent_device;
165
166 cd->event_handler(cd);
167
168 return IRQ_HANDLED;
169 }
170
171 static struct irqaction timer_iact = {
172 .name = "timer",
173 .flags = IRQF_TIMER,
174 .handler = timer_interrupt,
175 .dev_id = &t64_clockevent_device,
176 };
177
timer64_init(void)178 void __init timer64_init(void)
179 {
180 struct clock_event_device *cd = &t64_clockevent_device;
181 struct device_node *np, *first = NULL;
182 u32 val;
183 int err, found = 0;
184
185 for_each_compatible_node(np, NULL, "ti,c64x+timer64") {
186 err = of_property_read_u32(np, "ti,core-mask", &val);
187 if (!err) {
188 if (val & (1 << get_coreid())) {
189 found = 1;
190 break;
191 }
192 } else if (!first)
193 first = np;
194 }
195 if (!found) {
196 /* try first one with no core-mask */
197 if (first)
198 np = of_node_get(first);
199 else {
200 pr_debug("Cannot find ti,c64x+timer64 timer.\n");
201 return;
202 }
203 }
204
205 timer = of_iomap(np, 0);
206 if (!timer) {
207 pr_debug("%pOF: Cannot map timer registers.\n", np);
208 goto out;
209 }
210 pr_debug("%pOF: Timer registers=%p.\n", np, timer);
211
212 cd->irq = irq_of_parse_and_map(np, 0);
213 if (cd->irq == NO_IRQ) {
214 pr_debug("%pOF: Cannot find interrupt.\n", np);
215 iounmap(timer);
216 goto out;
217 }
218
219 /* If there is a device state control, save the ID. */
220 err = of_property_read_u32(np, "ti,dscr-dev-enable", &val);
221 if (!err) {
222 timer64_devstate_id = val;
223
224 /*
225 * It is necessary to enable the timer block here because
226 * the TIMER_DIVISOR macro needs to read a timer register
227 * to get the divisor.
228 */
229 dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_ENABLED);
230 }
231
232 pr_debug("%pOF: Timer irq=%d.\n", np, cd->irq);
233
234 clockevents_calc_mult_shift(cd, c6x_core_freq / TIMER_DIVISOR, 5);
235
236 cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
237 cd->max_delta_ticks = 0x7fffffff;
238 cd->min_delta_ns = clockevent_delta2ns(250, cd);
239 cd->min_delta_ticks = 250;
240
241 cd->cpumask = cpumask_of(smp_processor_id());
242
243 clockevents_register_device(cd);
244 setup_irq(cd->irq, &timer_iact);
245
246 out:
247 of_node_put(np);
248 return;
249 }
250